Ion flow across polarized epithelia is a tightly regulated process. Measurement of the transepithelial resistance is a highly relevant parameter for assessing the function or health of the tissue. Dynamic, electrical measurements of transepithelial ion flow are preferred as they provide the most accurate snapshot of effects of external stimuli. Enteric pathogens such as Salmonella typhimurium are known to disrupt ion flow in gastrointestinal epithelia. Here, for the first time, the use of organic transistors as a powerful potential alternative for front-line, disposable, high-throughput diagnostics of enteric pathogens is demonstrated. The transistors' ability to detect early and subtle changes in transepithelial ion flow is capitalized upon to develop a highly sensitive detector of epithelial integrity. Stable operation of the organic devices under physiological conditions is shown, followed by dynamic, pathogen-specific diagnosis of infection of epithelia. Further, operation of the device is possible in complex matrices, showing particular promise for food and safety applications.